Ligament fixation device and method

ABSTRACT

The invention relates to a device for attaching a ligament graft to the inside of a bone passage from a proximal location, the device including (1) a non-expansible ring having an interior passage through which the ligament graft may extend, the ring sized to fit within the bone passage; (2) a radially expansible gripping member sized to enter the ring and to press the ligament outwardly against the interior surface of the ring; and (3) an expander coupled to the expansible gripping member, constructed to expand the expansible gripping member to grip the ligament against the ring.

BACKGROUND OF THE INVENTION

[0001] This invention relates to fixation of ligament grafts.

[0002] When a ligament ruptures, it is usually replaced by a ligamentgraft or a prosthetic ligament. In many cases, a ligament graft ispreferable because prosthetic ligaments can wear out.

[0003] For example, the anterior cruciate ligament (ACL) when ruptured,often requires replacement and a graft is preferred.

[0004] In such ACL reconstruction procedures, a bone tunnel is createdthrough the tibia and one through the femur. The ligament graft is thenaffixed to each bone tunnel by a variety of means, with the goal thatthe graft will securely heal to the bone in the tunnel.

[0005] Presently available techniques are not satisfactory in allrespects.

SUMMARY OF THE INVENTION

[0006] According to one aspect of the invention a device is provided forattaching a ligament graft to the inside of a bone tunnel from itsproximal aspect (extra-articular point of access). The device comprises:a non-expansible ring having an interior passage through which theligament graft may extend, the ring sized and adapted to fit within andbe secured in the bone tunnel; a radially expansible gripping membersized to enter the ring and to press the ligament outwardly against theinterior surface of the ring; and an expander coupled to the expansiblegripping member, constructed to expand the expansible gripping member togrip and secure the ligament against the ring.

[0007] Preferred embodiments of this aspect of the invention have one ormore of the following features.

[0008] The gripping member, when in position within the ring, has adistal portion extending beyond the ring that positions a correspondingportion of the ligament near or against the surface of the bone tunnel,in the path of in-growing bone.

[0009] The ring is rigid.

[0010] The ring includes at least one aperture disposed to permitin-growth of bone through the side of the ring and about the ligamentgraft.

[0011] The device further comprises at least one strut extendingdistally from the ring and a distal member is disposed at the distal endof the strut in position to limit distal movement of the grippingmember. Preferably there are one strut or two spaced apart struts thatextend distally, in supporting relationship with said distal member.Preferably the distal member is a base from which a threaded rod extendsproximally through the ring passage, the gripping member being expandedby a threaded expander engaged upon the threaded rod, preferably thethreaded expander being of wedge form, arranged to radially wedge apartportions of the expansible gripping member.

[0012] Preferably, in the foregoing case or generally, a strut extendsproximally from the ring to a securing member attached to its proximalend, the securing member being constructed and arranged to engage anexterior surface of the bone to secure the ring in the cortical regionof the bone passage.

[0013] The expansible gripping member comprises a set ofcircumferentially arranged proximally extending leg portions constructedand arranged to be splayed apart by the wedging action of a centrallyintroduced expander member, preferably the exterior surface of thegripping member leg portions have ligament gripping projections. Incertain preferred embodiments the gripping projections comprise portionsof at least one barb or ledge and preferably an axially spaced set of,circumferential ledge or barb and in other preferred embodiments thegripping projection comprise screw threads, including lands, preferablyof helical form.

[0014] The ring supports a threaded rod that extends through thegripping member, in combination with a threaded expander wedge memberconstructed and arranged to be threaded on the threaded rod into theexpansible gripping member in a wedging relationship.

[0015] The expansible gripping member supports a threaded rod extendingproximally from the gripping member in combination with a threadedexpander wedge constructed and arranged to be threaded on the threadedrod into the expansible gripping member in a wedging relationship.

[0016] An expansible gripping member has a distally extending formationarranged to deflect to lock the gripping member in position relative tothe ring, preferably this formation comprising a set ofcircumferentially arranged, resilient fingers that are preferablyintegral with the main body of the gripping member.

[0017] An expansible gripping member has screw threads on its exteriorthat are disposed to engage and thread into ligament graft lying betweenthe ring and the gripping member during advance of the gripping member.

[0018] The expansible gripping member supports a threaded rod extendingproximally from the gripping member in combination with a threadedexpander wedge threaded into the gripping member for a wedgingrelationship.

[0019] According to another aspect of the invention a device is providedfor attaching a ligament graft to the inside of a bone tunnel from itsproximal aspect (extra-articular point of access), the devicecomprising: a non-expansible structure ledge providing an interiorpassage through which the ligament graft may extend, the structure sizedand adapted to fit within and be secured in the bone tunnel; a grippingmember sized to be opposed to the ledge structure and to grip theligament against a portion of the structure; and at least one strutextending distally from the portion of the ledge structure against whichthe ligament is gripped, a distal member disposed at the distal end ofthe strut in position to limit distal movement of the gripping member.

[0020] In preferred embodiments of this aspect of the invention thegripping member is expansible radially to grip the ligament against theledge structure and position the ligament for incorporation by in-growthof bone from the wall of the tunnel. Preferably the ledge structure iscarried on a continuous ring.

[0021] According to another aspect of the invention a device is providedfor attaching a ligament graft to the inside of a bone tunnel from anextra-articular location, the device comprising: a rigid ring having aninterior passage through which the ligament graft may extend, the ringsized and adapted to fit within and be secured in the bone tunnel; agripping member constructed and arranged to grip a ligament graftagainst the interior surface of the rigid ring; and at least one strutextending proximally from the ring, a securing member attached to theproximal end of the strut, the securing member sized to engage anexterior surface of the bone to secure the ring in the cortical regionof the bone tunnel.

[0022] Preferably the peripheral outer surface of the ring iscylindrical.

[0023] Preferred embodiments of this aspect of the invention have abone-penetrating formation carried by the securing member.

[0024] Preferably the securing member is a flange extending laterallyfrom the axis of the passage; preferably the flange has bone-penetratingformation, preferably projecting distally toward the bone.

[0025] In other embodiments the securing member is a flange having ahole sized to receive an awl-like tool to hold the member in positionagainst rotation while a portion of the device is turned during theprocedure.

[0026] Preferably, the gripping member is expansible to grip theligament against the ring, and an expander is coupled to the expansiblegripping member, constructed to expand the gripping member to grip theligament against the ring.

[0027] Preferably the gripping member, when in position within the ring,has a distal portion extending beyond the ring that positions acorresponding portion of the ligament near or against the surface of thebone passage in the path of in-growing bone.

[0028] According to another aspect of the invention, a device isprovided for attaching a ligament graft to the inside of a bone tunnelfrom its proximal aspect, the device comprising: a non-expansible ringhaving an interior passage through which the ligament graft may extend,the ring sized and adapted to fit within and be secured in the bonepassage; strut portions extending proximally and distally from the ring;a securing member attached to the end of the proximally-extending strutportion, the securing member sized to engage an exterior surface of thebone to secure the ring in the cortical region of the bone tunnel; abase member attached to the distal end of the distally extending strutportion; a rod extending proximally from the base member through thering; and a gripping member disposed between the rod and the ring, thegripping member constructed to grip the ligament against the ring.

[0029] Preferably the gripping member is expansible to grip the ligamentagainst the ring.

[0030] According to another aspect of the invention a method is providedfor attaching a ligament graft to the inside of a bone tunnel from aproximal location, the method comprising: providing a device accordingto any of the aspects of the invention, that have been described;providing a bone tunnel within a bone; introducing a non-expansiblering, or a rigid ring, with a ledge structure into the bone passage;passing the ligament graft through the interior passage of theintroduced element; inserting a gripping member and expanding orotherwise urging the gripping member into a position that the grippingmember grips the ligament against the introduced element, therebysecuring the ligament graft to the inside of the bone tunnel. Inpreferred embodiments an expander is screwed into the gripping member orthe radially expansible gripping member is screwed into the interiorpassage of the ring.

[0031] In the case of cruciate ligament graft, in which the graft issecured to the femur, the device is preferably introduced at anextra-articular location. Preferably multiple, e.g. 4, strands of graft,e.g. tendon, extend through the tunnel, preferably each of the grafts orat least pairs of grafts, being separated from the others in positionfor individual incorporation into in-growing bone.

BRIEF DESCRIPTION OF DRAWINGS OF PREFERRED EMBODIMENTS

[0032]FIG. 1 is a side view of components that comprise a preferredligament fixation set according to the invention.

[0033]FIG. 1A is a distal end view and FIG. 1B a proximal end view of anexpandable gripping element component of the set taken respectively onlines 1A-1A and 1B-1B of FIG. 1.

[0034]FIG. 1C is a cross-sectional view taken on-line 1C-1C of FIG. 1,showing features of the fixed ring member.

[0035]FIG. 1D is a cross-section profile of the ring element of thefixed ring member taken on lines 1D-1D of FIG. 1C.

[0036]FIG. 2 is a view similar to FIG. 1 of another preferred fixed ringmember while FIG. 2A is a partial side view of another preferredconstruction.

[0037]FIG. 3 is an assembly view, with ligament graft in place, showingthe expandable gripping element seated in the fixed ring member by thedriving component of the fixation set of FIG. 1.

[0038]FIG. 3A is a cut away view of part of the assembly of FIG. 3showing details of the seating of the distal end of the grippingelement.

[0039]FIG. 4 shows the expandable assembly of FIG. 3 with the grippingelement now expanded by action of a conical wedge member of the set ofFIG. 1.

[0040]FIG. 4A is a diagrammatic view on an enlarged scale of thegripping action of the expanded gripping member against a preferredledge formation of a fixed ring member.

[0041]FIG. 5 is a diagrammatic view of the ligament fixation device ofFIG. 1 in place in a tibia tunnel, securing replacement ligaments in theknee.

[0042]FIGS. 6 through 6E are views of the tibia of FIG. 5 illustratingthe sequence of steps for placing the device in the tibia.

[0043]FIGS. 7A through 7C are views of another embodiment of theinvention illustrating the sequence of steps for placing the device inthe tibia.

[0044]FIG. 7D is an enlarged view showing a fixed ligament using thedevice shown in FIG. 7C.

[0045]FIG. 8 is a view similar to parts of FIG. 7A of another embodimentof the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0046]FIG. 1 shows five parts that comprise a ligament fixation set. Afixed ring member 10 has ring element 11 that has on its inner peripherya fixed ledge 12 (See FIGS. 1C, 1D). The ring element 11, here in theform of a rigid cylindrical wall, has a series of in-growth apertures 13formed in the wall. A pair of opposed distally extending struts 16 areintegral with ring 11. Both extend distally to base 18. One of thestruts has a proximally extending portion 16A which extends proximallyto a retaining flange 14. The flange of Strut 16 a serves as a buttressagainst the tibial cortex at the beginning of a tunnel in the tibia, theremainder of the device being sized to extend into the tunnel. Base 18of ring member 10 supports a shaft that defines a threaded rod 20 thatextends axially, parallel to struts 16 and proximally beyond ringelement 11 to a joint 24 aligned with flange 14. A threaded rodextension 22 lying on the same axis is connected to threaded rod 20 bysnap joint 24. At the proximal tip of the threaded rod extension is areduced diameter pilot portion 23.

[0047] An expander formation 26 is formed as part of the shaft close to,but spaced proximally from base 18. The space between the expander andthe base provides a relief region 28 defined by a reduced diameterportion at the root of the shaft.

[0048] The expandable gripping element 30 defines distal expansionsliding fingers 31 that are designed to resiliently spread and slideover the expander formation 26, and contract into the relief region 28,see FIG. 3A. The expandable gripping element 30 has angular grippingteeth 32 or ridges arranged to apply pressure to the ligament graft. Theexpandable gripping element 30 has proximal expansion slots 34 thatallow expansion of distally extending, resilient portions of theexpandable gripping element 30 by the conical wedge 42.

[0049] Also provided in the fixation set is driving nut 36 which hasinternal threads 37, matched to the external threads of the threaded rod20, 22. The driving nut 36 has a driving head 38 for engagement by ahand powered driver 40 which is included in the fixation set. Only aportion of the driver is shown in FIG. 1. The remaining portioncomprises a hollow shaft and handle such as that of a screw driver.

[0050] Also included in the set is conical wedge member 42. It hasinternal threads 43 also matched to the rod and a driving head 44 forengagement by driver 40.

[0051] An alternative construction of the ligament fixation device isshown in FIG. 2. In this case one of the struts 16 of the ring memberhas been eliminated. In the further embodiment of FIG. 2A, similar tothat of FIG. 2, bone penetrating formations 46 depend from flange 14,for penetrating the tibia and locking the ring member from rotation.

[0052] In another embodiment a hole is provided in a flange for use of aawl-type instrument to securely hold the fixed ring member opposed tothe tibia-during the fixation procedure.

[0053] Use of the Ligament Fixation Device

[0054] Arthroscopic assisted ligament reconstruction of the kneerequires rigid fixation of ligament grafts to bone. This enablesaccelerated rehabilitation and achievement of a stable knee. The presentdevice enables secure fixation of soft tissue grafts, such as harvestedtendons, to the endosteal surface of bone, that avoids reliance uponcompression of the grafts against cancellous bone, and thus the strengthof the fixation does not depend upon the underlying strength of thecancellous bone, and therefore promotes early rehabilitation even in thecase of relatively soft cancellous bone.

[0055] In conjunction with the use of the ligament fixation devicedescribed, the grafts are secured on the femoral side of the knee usingany of several methods. A common technique is to loop the tendons arounda fixed post that is either attached to a button on the outer cortex ofthe femur or is placed directly across the femoral tunnel. Typicallyfour strands of tendon are disposed across the knee joint forreconstructing the new ligament, which exit the joint through a tibialtunnel, to the outer cortex of the tibia.

[0056] Referring to FIG. 5, a ligament reconstruction technique isillustrated, that employs the device of the invention. Four ligamentgraft strands 48 extend from loops about a secure ring 52 which isattached to a button device 50 that is placed across the femoral tunnel51. The four ligament grafts 48 traverse the tibial tunnel 54 and exiton the outer cortex of the tibia, 56.

[0057]FIG. 6 shows the four graft strands traversing the tibial tunnel60 before the fixation device is in place. FIG. 6A illustratesintroduction of the fixed ring member 10 in a fashion whereby two of theligament grafts 48 pass on one side of the base 18 and two of theligament grafts 48 pass on the other side. The ring member is insertedinto the tibia tunnel 54 from the proximal aspect to the point where theretaining flange 14 is securely lodged upon the tibial cortex 15 asshown in FIG. 6A. If bone penetrating formations 46 as shown in FIG. 2aare employed, these penetrate the cortex and add to the action of theretainer flange 14 in securing the device to the tibial cortex. As shownin 6B, the expandable gripping element 30 is introduced into theligament fixation ring member by sliding it over the pilot portion 23 ofthe threaded rod extension 22. The driving nut 36 is then also placed onthe threaded rod extension 22, being introduced over pilot portion 23 ofthe rod. The driver 40 is then placed upon the driving head 38, androtated clockwise to introduce the expandable gripping element into thefixation device to the point where the fingers defined by distalexpansion slots 31 resiliently lock over the expander ledge 26, as shownin FIG. 3A. The driving nut 36 provides axial force to thus implant theexpandable gripping element 30 in the device.

[0058] The driving nut 36 is then removed from the fixation device byrotating the driver 40 counterclockwise. As suggested in FIG. 6D, theconical wedge member 42 is then threaded on the threaded rod extension22 over the pilot portion 23. The conical wedge is rotated past the snapjoint 24 to the threaded rod region 20. It is driven into the expandablegripping element 30 by further rotation of the driver 40 until it isseated as is shown in FIG. 6E. As it is seated, the conical wedgesurface 42 expands the proximal leg portions of the expandable grippingelement 30, a motion permitted by the proximal expansion slots 34 formedin the member. The expanded condition obtained is shown in FIG. 4.Suitably high compression is developed between the expandable grippingelement 30 and the interior surface of ring 11. The ligament grafts 48which are separately disposed between ring 11 and expandable grippingelement 30 are thus gripped securely by the expansion of expandablegripping element 30 toward the inner surface of ring 11. Where, as inthe embodiment of FIG. 4A, an internal stress concentrating ledge 12 isprovided on the ring, the maximum compression and securing action on theligaments occurs in the vicinity of this ledge.

[0059] After suitable compression upon the ligament grafts has beenachieved, the driver 40 is disengaged from the conical wedge and thethreaded rod extension 22 is disengaged from the threaded rod 20 bybending applied to snap joint 24, that joint having been preselected toproduce fracture under pressures that are not disruptive of the now-inplace fixation device.

[0060] Recapping FIGS. 6-6C, FIG. 6 shows the four discrete ligamentgrafts traversing the tibial tunnel 60, FIG. 6a shows the introductionof the fixed ring member 10 with one pair of the ligament grafts 48 onone side and another pair of ligament grafts 48 on the other side ofbase 18, with the grafts exiting the tibial tunnel 54 through the fixedring member 10. As shown in FIG. 6B, the expandable gripping element 30is introduced by use of driving nut 36, the expandable gripping element30 being driven into the fixed ring member 10 until the resilientelements forming its distal tip (enabled by distal expansion slots 31)have snapped over the expander ledge 26 as shown in FIG. 3A. The conicalwedge 42 is introduced, FIG. 6D, to the point where the expandablegripping element 30 is compressed greatly against the inner aspect ofthe ring element 11, see FIGS. 4 and 4A.

[0061] As shown in FIG. 6E, the threaded rod extension 22 has beenremoved from the threaded rod 20 leaving the final fixation deviceconfiguration, i.e. the fixed ring member 10, securely implanted in thetibia with the expandable gripping element 30 compressed by the in-placeconical wedge member 42. FIG. 4 shows the conical wedge member 42expanding the expandable gripping element 30 within the fixed ringmember 10. The ligament grafts 48 are cut off at the end of theprocedure, shown as dotted line “C” in FIG. 6E.

[0062] Referring to the magnified view of FIG. 4A the ligament grafts 48are shown wedged outwardly by the expandable gripping element 30. In theinner aspect of this embodiment of the ring element 11 there is arelatively narrow fixation ledge 12, at which the ligament grafts aretightly gripped with suitable non-damaging distortion of the grafts. Theligament grafts are transected at the end of the procedure just beyondthe ring element 11. FIGS. 5 and 6E show by dotted line where theligament grafts 48 are transected at the end of the procedure. Theexpandable portion of the distal aspect of the expandable grippingelement provides an indication that the gripping element has beensecurely placed down to the base, which limits its motion and hencelimits the available wedging movement to an appropriate amount. A markon the driver or a mark on the flange may provide a visual verificationthat the gripping element has fully seated.

[0063] Operative Technique for Ligament Fixation Device

[0064] The arthroscopic assisted ACL reconstruction is performed withthe leg either bent over the end of an operating room table or with theknee bent but with the patient supine on an operating table. Usinghamstring tendons as the ligament graft requires the use of an incisionon the proximal medial tibia of about 3 finger breadths length, placedjust medial to the tibial tunnel. Through this incision the gracilis andsemitendinosus tendons can be obtained as free grafts to reconstruct theanterior cruciate ligament.

[0065] A tunnel is drilled through this incision into the knee underarthroscopic visualization (all portions of the procedure that are to beperformed intra-articularly are done under visualization by way of thearthroscope).

[0066] The tunnel which begins on the anteromedial tibia enters theintra-articular portion of the tibia at the insertion point of theanterior cruciate ligament on the tibia. Through this tibial tunnel asecond tunnel is drilled into the femur. The second tunnel is placed atthe second attachment site of the anterior cruciate ligament.

[0067] At this point there are two tunnels in the knee, one from theexterior portion of the tibia to the intra-articular region, and asecond one in the femur, both tunnels as depicted in FIG. 5.

[0068] These tunnels are placed such that their openings are at thenormal anterior cruciate origin and insertion sites.

[0069] At this point the grafts are placed across the knee, usually byuse of sutures that are drilled through the lateral cortex of the femurand brought out to the lateral aspect of the thigh. The looped ends ofthe grafts are brought up into the femoral tunnel where they are securedby looping them around either a fixed post or the secure loop extendingfrom a metal button as shown in FIG. 5. The grafts then lie across theknee joint in the anatomic configuration of the anterior cruciateligament. They exit through the tibial tunnel and are splayed outthrough the incision on the proximal medial tibia.

[0070] These tendon grafts need to be securely fixed on the tibial side.

[0071] Many previous operative techniques have relied upon staples orscrews and washers to secure tendon grafts to the tibial corticalsurface. These fixation techniques leave painful, prominent hardwaredirectly beneath the skin, their fixation strength is not alwaysreliable, and a certain portion of tendon beneath these compressivedevices is devascularized, that can be injurious.

[0072] The ligament fixation device here-described rigidly secures theligament grafts within the tibial tunnel and leaves no prominenthardware. The construction enables in-growth of cancellous bone directlyto the ligament grafts through apertures in ring element 11 and in theregion just distal of ring element 11 where the tendons have beensplayed out against or close to cancellous bone tissue.

[0073] The ligament fixation device thus provides temporary fixationuntil the body's normal healing process incorporates the ligament graftsinto the bone. It is known from animal studies and clinical experiencethat by eight weeks, ligament grafts have incorporated into bone suchthat the weakest link of the new ligament construct is no longer thefixation point, but rather the intra-articular portion of the ligament.The presently preferred ligament fixation device provided herein has arelatively narrow ring element that minimizes the compression of thesoft ligament tissue, the device providing a large open region distal tothe ring element where the expandable gripping element pushes theligament grafts into intimate contact with the cancellous bone tofacilitate early healing of the grafts to the cancellous bone.

[0074] The rigid fixation of the hamstring grafts, thus achieved, canfacilitate an accelerated rehabilitation, whereby a full range of motionand weight bearing, as tolerated, are begun based on patient comfort andnot on any concern for protection of the fixation region.

[0075] An advantage of the ligament fixation device is that all of theligament grafts are securely opposed to bone, allowing healing of eachgraft to bone so as to obtain the full strength potential of thecomposite.

[0076] Other Embodiments

[0077] In another embodiment, as shown in FIG. 7A, a fixed ring member111 is implanted into a tibial tunnel 154, fixed ring member 111 beinginternally open, not having a threaded rod. A pair of opposed struts 116are integral with ring 111 and support base 118 in position to limitdistal advance of gripping element 130. Referring to FIG. 7A, thegripping element 130 has screw thread formations 132 on its conicalexterior, constructed to be screwed into portions of graft 148 withinring member 111. Referring to FIG. 7B, the gripping element 130 isintroduced to ring member 111 by rotation until its proximal end isroughly flush with ring member 111, at which point thread formations 132interact with graft 148 to provide the reaction force that enablesgripping element 130 to be driven into the tibial tunnel and into theinner portion of ring member 111. In so doing, the thread formations 132of gripping element 130 deform the tendon (see FIG. 7D) and therebydefine its path into ring member 111.

[0078] In a preferred modification shown in FIG. 8, a screw-formgripping member 230 has a hollowed bore 231 in its proximal portion andis expandable much in the nature of the expandable gripping element ofFIG. 1. When seated, screw 230 is expanded securely toward ring member111 by a second conical member 242 that is turned into bore 231 of theembodiment of FIG. 8 either by a threaded rod 222 incorporated into theplastic screw 230, extending proximally for receiving an expander 242which may be identical to wedge member 42 of FIG. 1, or by the action ofscrew threads on the conical surface, that interact with the interiorsurface of the gripping element.

[0079] In a further alternative, the support base section may beomitted.

[0080] In preferred embodiments the ring member including its struts,base and flange are formed integrally of biologically acceptable, strongmetal. The expansible gripping member advantageously is of one piececonstruction of engineering plastic that has suitable resiliency.

[0081] Numerous other embodiments employ other details to achieve securefixation following the principles at various levels of generality, thathave been presented here.

What is claimed is:
 1. A device for attaching a ligament graft to theinside of a predetermined bone tunnel from its proximal aspect, thedevice comprising: a non-expansible ring having an interior passagethrough which the ligament graft may extend, the ring sized and adaptedto fit within and be secured in the bone tunnel; a radially expansiblegripping member sized to enter the ring and to press the ligamentoutwardly against the interior surface of the ring; and an expandercoupled to the expansible gripping member, constructed to expand theexpansible gripping member to grip the ligament against the ring.
 2. Thedevice of claim 1 in which the ring is sized smaller than the tunnel andincluding a securing device located proximally of the ring.
 3. Thedevice of claim 1 including a strut which extends proximally to asecuring member attached to its proximal end, the securing memberconstructed and arranged to engage an exterior surface of the bone andto secure the ring in the cortical region of the bone passage.
 4. Thedevice of claim 1 wherein the ring is rigid.
 5. The device of claim 1 inwhich the gripping member, when in position within the ring, has adistal portion extending beyond the ring that positions a correspondingportion of the ligament graft against or near the surface of the bonetunnel, in the path of in-growing bone.
 6. The device of claim 1 whereinthe ring includes at least one aperture disposed to permit in-growth ofbone about the ligament graft.
 7. The device of claim 1 , furthercomprising: at least one strut extending distally from the ring; and adistal member disposed at the distal end of the strut in position tolimit distal movement of the gripping member.
 8. The device of claim 7in which there are at least two spaced apart struts that extenddistally, in supporting relationship with said distal member.
 9. Thedevice of claim 7 in which the distal member is a base from which a rodextends proximally through the ring passage, upon which a member acts toexpand the gripping member.
 10. The device of claim 9 in which the rodis threaded and the gripping member is associated with a threadedexpander engaged upon the threaded rod for expanding the expansiblemember.
 11. The device of claim 10 in which the threaded expander is ofwedge form, arranged to radially wedge apart portions of the expansiblegripping member.
 12. The device of claim 9 , wherein a strut extendsproximally from the ring to a securing member attached to its proximalend, the securing member constructed and arranged to engage an exteriorsurface of the bone and to secure the ring in the cortical region of thebone passage.
 13. The device of claim 1 in which the expansible grippingmember comprises a set of circumferentially arranged proximallyextending leg portions constructed and arranged to be splayed apart bywedging action of a centrally introduced member.
 14. The device of claim13 in which the exterior surface of the leg portions have ligamentgripping projections.
 15. The device of claim 14 in which the grippingprojections comprise portions of at least one circumferential ledge,barb or tooth.
 16. The device of claim 14 in which the grippingprojections comprise screw threads.
 17. The device of claim 14 in whichthe ring supports a threaded rod that extends through the grippingmember, in combination with a threaded expander wedge constructed andarranged to be threaded on the threaded rod into the expansible grippingmember in a wedging relationship.
 18. The device of claim 14 in whichthe expansible gripping member supports a threaded rod extendingproximally from the gripping member in combination with a threadedexpander wedge constructed and arranged to be threaded on the threadedrod into the expansible gripping member in a wedging relationship. 19.The device of claim 14 in which the expansible gripping member has adistally extending formation arranged to deflect to lock the grippingmember in position relative to the ring.
 20. The device of claim 14 inwhich the expansible gripping member has screw threads on its exteriorthat are disposed to engage and thread into ligament graft lying betweenthe ring and the gripping member during advance of the gripping member.21. The device of claim 1 in which the expansible member supports athreaded rod extending proximally from the gripping member incombination with a threaded wedge element constructed and arranged to bethreaded on the threaded rod into the expansible gripping member in awedging relationship.
 22. A device for attaching a ligament graft to theinside of a bone tunnel from a proximal aspect, the device comprising: anon-expansible ledge structure providing an interior passage throughwhich the ligament graft may extend, the structure sized and adapted tofit within and be secured in the bone tunnel; a gripping member sized tobe opposed to the ledge structure and to grip the ligament against aportion of the ledge structure; and at least one strut extendingdistally from the portion of the ledge structure against which theligament is gripped, a distal member disposed at the distal end of thestrut in position to limit distal movement of the gripping member. 23.The device of claim 22 in which the gripping member is expansibleradially to grip the ligament against the ledge structure and positionthe ligament for incorporation by in-growth of bone from the wall of thetunnel.
 24. The device of claim 22 in which the ledge structure iscarried on a continuous ring.
 25. A device for attaching a ligamentgraft to the inside of a bone tunnel from an extra-articular location,the device comprising: a rigid ring having an interior passage throughwhich the ligament graft may extend, the ring sized to fit within thebone tunnel; a gripping member constructed and arranged to grip aligament graft against the interior surface of the rigid ring; and atleast one strut extending proximally from the ring, a securing memberattached to the proximal end of the strut, the securing member sized toengage an exterior surface of the bone to secure the ring in thecortical region of the bone tunnel.
 26. The device of claim 25 in whichthe peripheral outer surface of the ring is cylindrical.
 27. The deviceof claim 25 in which a bone-penetrating formation is carried by thesecuring member.
 28. The device of claim 25 in which the securing memberis a flange.
 29. The device of claim 28 in which the flange hasbone-penetrating formations.
 30. The device of claim 25 in which thesecuring member is a flange having a hole sized to receive an awl-liketool to hold the member in position against rotation while a portion ofthe device is turned during the procedure.
 31. The device of claim 25 inwhich the gripping member is expansible to grip the ligament against thering; and an expander is coupled to the expandable gripping member,constructed to expand the gripping member to grip the ligament againstthe ring.
 32. The device of claim 31 in which the gripping member, whenin position within the ring, has a distal portion extending beyond thering that positions a corresponding portion of the ligament near oragainst the surface of the bone passage in the path of in-growing bone.33. A device for attaching a ligament graft to the inside of a bonetunnel from a proximal aspect, the device comprising: a non-expansiblering having an interior passage through which the ligament graft mayextend, the ring sized and adapted to fit within and be secured in thebone passage; strut portions extending proximally and distally from thering; a securing member attached to the end of the proximally-extendingstrut portion, the securing member sized to engage an exterior surfaceof the bone to secure the ring in the cortical region of the bonetunnel; a base member attached to the distal end of the distallyextending strut portion; a threaded rod extending proximally from thebase member through the ring; and a gripping member disposed between therod and the ring, the gripping member constructed to grip the ligamentagainst the ring.
 34. The device of claim 25 in which the grippingmember is expansible to grip the ligament against the ring.
 35. A methodof attaching a ligament graft to the inside of a bone tunnel from aproximal location, the method comprising: providing a device comprisingproviding a structure comprising a non-expansible ring, a rigid rings,or a ledge structure that provides an interior passage through which theligament graft may extend, the structure sized to fit within the bonetunnel; a gripping member sized to press the ligament outwardly againstthe interior surface of the structure; and providing a cylindrical bonetunnel within a bone; inserting the non-expansible ring into the bonetunnel; passing the ligament graft through the interior passage of thering; inserting the gripping member through the interior passage of thering; expanding or otherwise urging the gripping member into a positionthat the gripping member grips the ligament against the structure,thereby securing the ligament graft to the inside of the bone tunnel.36. The method of claim 35 , wherein an expander is screwed into agripping member to expand it to grip the ligament graft.
 37. The methodof claim 35 , wherein a radially expansible gripping member is screwedinto the interior passage of the ring.
 38. The method of claim 35employed in cruciate ligament grafts in which the graft is secured tothe femur.
 39. The method of claim 38 in which multiple strands of graftextend through the tunnel and are affixed in spaced apart positions.